821253678 has 32 divisors (see below), whose sum is σ = 1881302784. Its totient is φ = 234124992.

The previous prime is 821253661. The next prime is 821253679. The reversal of 821253678 is 876352128.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821253679) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2200 + ... + 40587.

It is an arithmetic number, because the mean of its divisors is an integer number (58790712).

Almost surely, 2^821253678 is an apocalyptic number.

821253678 is an abundant number, since it is smaller than the sum of its proper divisors (1060049106).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

821253678 is a wasteful number, since it uses less digits than its factorization.

821253678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43256.

The product of its digits is 161280, while the sum is 42.

The square root of 821253678 is about 28657.5239335153. The cubic root of 821253678 is about 936.4669236037.

The spelling of 821253678 in words is "eight hundred twenty-one million, two hundred fifty-three thousand, six hundred seventy-eight".